The present invention relates to devices and instruments for use in assembling a disc drive assembly and its sub-assemblies. In particular, the present invention relates to an electrical grounding device electrically coupled to a dispenser for dispensing fluids, such as glue and epoxy, upon a surface of the disc drive assembly which is in electrical contact with a magnetic head of the assembly.
The magnetic head stores and retrieves information on a magnetic disc. Several types of magnetic heads are currently in use, including metal-in-gap (MIG) heads, thin film (TF) heads and magnetoresistive (MR) heads. Due to the continual drive to increase storage density in magnetic disc drive units, magnetic heads have become increasingly advanced and sensitive.
Typically, a magnetic head consists of a slider and a transducer. The slider carries the transducer and flies over the surface of the magnetic disc as the disc rotates. The transducer reads and/or writes to the magnetic disc. Electric signals are provided to and received from the transducer via conductors which are typically twisted wires. A glue, such as fluid epoxy, attaches wires or tacks the wires to bonding pads and sides of the slider. This tacking process, otherwise known as conformal coating, actually coats the wire where the wire is attached to the slider. As a result, the conformal coating process prevents the wires from being pulled loose and also protects the wires from corrosion.
The slider of the magnetic head is supported above the magnetic disc as part of a head/gimbal assembly. As described in Hagen U.S. Pat. No. 5,027,239, herein incorporated by reference, the head-gimbal assembly typically includes at least one support arm, a load beam, a gimbal and the magnetic head discussed above. The support arm is attached to the load beam by a well-known technique referred to as swaging or ball staking. The load arm carries the load beam. The load beam is attached, preferably by laser welding, to the gimbal. Lastly, the gimbal is preferably glued to the slider of the magnetic head by fluid epoxy or other conventional adhesive materials. Typically, the fluid, such as glue or fluid epoxy, applied to surfaces of the slider and the gimbal is dispensed onto the surface from a dispensing syringe which is positioned and controlled either manually or by an automated process.
IBM TDB vol. 37, no. 2A, February 1994, entitled "Hand tools grounding for manufacturing sensitive parts assemblies" discloses a kit for fitting to an existing small hand tool such as a commercial screwdriver with a plastic handle, the kit comprising a number of fingers extending from a central aperture through which the end of the tool is inserted. The fingers are stuck to the handle of the tool and comprise electrostatic discharge material for preventing static build-up at the end of the tool.
FR-A-2646491 discloses a suction tube for grasping and transporting semiconductor devices having a conductive insert for making an electrical connection between the end of the tool contacting the semiconductor devices and a carbon fibre body of the tool, such as to conduct away from the tool end electrostatic charge.
Neither of these disclosures are concerned with a dispenser for dispensing fluid to surfaces of a disk drive assembly. Such dispensers frequently suffer from a problem of electrostatic charge build-up at the surface of the dispenser close to the disk drive assembly.